Abstract:To balance the charging efficiency and service life, lithium-ion batteries usually require constant current followed by constant voltage charging mode. A switchable series hybrid topology WPT system for charging lithium-ion batteries has been introduced in this paper. The system can be switched from constant current mode to constant voltage mode without real-time feedback from secondary sides and complex control strategies. Firstly, based on the T model, a theoretical analysis of the hybrid topology has been carried out, which deduced that the hybrid topology WPT system outputs load-independent constant current and constant voltage at constant frequency and zero phase angle. Secondly, a model has been built in the power electronics simulation software to analyze the operating characteristics of the two topologies in constant voltage mode and system efficiency. Finally, a WPT experimental platform with a charging current of 3.5 A and a charging voltage of 65 V has been built. The experimental results showed that the current fluctuation is less than 5.9% in constant current mode and the voltage fluctuation is less than 8% in constant voltage mode over a wide range of loads.